The San Diego County Experimental Base Project, which was constructed in 1966 and continued until 1973, was a test road consisting of 35 different sections designed to measure the performance of granular and asphalt-bound base courses. This paper presents an analysis of the test-road sub-grade and its variability. Multiple regression analysis has shown that the subgrade resilient modulus can be correlated with the soil moisture and degree of saturation and that the ratio of the laboratory modulus to the field modulus is near unity for high degrees of saturation. For lower degrees of saturation (80 to 85 percent), laboratory-compacted samples tended to have higher values of the modulus than did field-compacted samples. On the average, for treated base sections, the in-place modulus predicted from regression analysis gave excellent agreement with values of the modulus derived from Benkelman-beam deflections in a multilayer elastic analysis. Because of an apparently stiffer in situ response of granular base material than was predicted in the laboratory, similar comparisons for granular base sections were not good. The modulus of granular base materials averaged six times greater in the field than in the laboratory. The test-road subgrade was not uniform, but was highly variable between and within test sections. Resilient-modulus tests of undisturbed field cores had a coefficient of variation of the modulus of approximately 97 percent between test sections. The coefficient of variation within test sections averaged approximately 40 percent.

Media Info

  • Media Type: Print
  • Features: Figures; References; Tables;
  • Pagination: pp 1-6
  • Monograph Title: Stabilization of soils
  • Serial:

Subject/Index Terms

Filing Info

  • Accession Number: 00177110
  • Record Type: Publication
  • ISBN: 0309026709
  • Files: TRIS, TRB
  • Created Date: Jun 28 1978 12:00AM